Impact of parthenium weed invasion on plants and their soil seedbank in a subtropical grassland, central Nepal

Khatri-Chettri Jyoti,Rokaya Maan Bahadur,Shrestha Bharat Babu 한국생태학회 2022 Journal of Ecology and Environment Vol.46 No.1

Background: Parthenium hysterophorus L. (Asteraceae; hereafter Parthenium) is an invasive alien species of global significance because of its’ negative ecological and socioeconomic impacts. This species is spreading rapidly from lowland Tarai to Middle Mountain regions in Nepal. In the present study, we analyzed the impacts of Parthenium on plant community composition including their soil seedbank in subtropical grasslands located in central Nepal. Data was collected in a 10 m long transects passing through areas of high (> 90% cover), medium (40%–60%) and low (< 10%) levels of Parthenium cover using a plot of 1 m2. Altogether, we sampled 90 plots in 30 transects. Seedling emergence method was used to estimate soil seedbank density in the soil samples (0–10 cm depth) collected from the plots with high Parthenium cover. Results: There was no significant difference in the plant species richness at different levels of Parthenium invasion whereas there was a significant change in the species composition of above ground flora due to Parthenium invasion. There was also a significant difference in species composition between soil seedbank and aboveground flora in the highly invaded plots. Parthenium was the most dominant in soil seedbank, contributing 65% to the total soil seedbank. Conclusions: Our study suggests that Parthenium has considerable negative impact on the native grassland flora, and the dominance of Parthenium in the soil seedbank means there is a challenge for its management. It also suggests the need of monitoring the soil seedbank dynamics while managing Parthenium weed.

Kitam Bird Sanctuary, the only low elevation protected area of Sikkim: A conservation hotspot for butterflies in the Eastern Himalaya

Sailendra Dewan,Iswar Kumar Chettri,Kishor Sharma,Bhoj Kumar Acharya 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.2

The lowland areas of the Himalayan region are subjected to immense anthropogenic pressure because of least representation in the protected area network. Kitam Bird Sanctuary is the only representative protected area that occurs below 1000 m in Sikkim state of India (a part of globally significant biodiversity hotspot of Himalayas) and serves as the refuge for various species of flora and fauna. Here we studied butterfly diversity and community composition in Kitam Bird Sanctuary (a small protected area of 6 km 2 geographical area) following point count method spread across predetermined transects. Altogether 1674 butterflies belonging to 111 species and six families were recorded after completion of 240 point counts. Among these, 18 species are federally protected under the Wildlife (Protection) Act (1972) of India. Most of the butterflies were forest specialist in terms of habitat preference, whereas based on host plant specificity, the butterfly community was mostly dominated by generalist feeder (Oligophagous II and Polyphagous). Butterfly community parameters showed a strong correlation with habitat variables. While Kitam Bird Sanctuary is primarily designated for conservation of lowland birds, the high diversity of butterflies both in terms of taxonomic richness and trait composition suggests that the sanctuary harbors an ideal habitat for butterflies of the tropical region and invites conservation attention.

부탄왕국의 벼 재배환경 및 재래종 품종의 지역분포

Tae Soon Kwak,GB Chettri 상지대학교 북방농업연구소 2003 북방농업연구논총 Vol.3 No.-

Mithun (Bos frontalis): the neglected cattle species and their significance to ethnic communities in the Eastern Himalaya - A review

Dorji, Tashi,Wangdi, Jigme,Shaoliang, Yi,Chettri, Nakul,Wangchuk, Kesang Asian Australasian Association of Animal Productio 2021 Animal Bioscience Vol.34 No.11

Objective: This review consolidates the available information on the socio-economic and ecological significance of Mithun in the lives of ethnic communities in the Eastern Himalaya. Methods: Standard guidelines were followed for the review and data collection was carried out at three stages; literature search, literature screening, and literature review and analysis. Results: Records indicate a long association of Mithun with the ethnic groups. Mithun serves as a symbol of pride and local currency for barter trade in the ethnic society. Its utilities range from being used as a bride price to settling legal disputes. Several cultural festivals and local ceremonies are celebrated around this bovine. Due to its semi-wild nature, this animal also has an ecological role to conserve broad leaf sub-tropical forests. However, it remains neglected and has not received policy attention, leading to a stagnated growth. The institutions for Mithun research and development are also weak. Furthermore, the species is under threat from new diseases and habitat alteration triggered by climate change. Conclusion: Founded on the current state of knowledge, there is a need for institutional development, strengthening institutional linkages, and promoting regional cooperation among Mithun rearing countries for further research and development of this unique cattle.

Realization of 4G Downlink Channel

Nigidita pradhan,Rabindranath Bera,Debasish Bhaskar,Preman Chettri 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.5

Today’s era people have grown in every field, such that their needs are also growing linearly with their advancement. This rapid development of broadband wireless access technologies in recent years was the result of growing demand for mobile Internet and wireless multimedia applications. Now it is becoming difficult to meet the demands of these data hungry people. So, the wireless network is advancing after 3G and providing better coverage, higher data rate and by reducing Latency. It uses the frame structure as Time Division Duplexing (TDD) and Frequency Division Duplexing (FDD).LTE technology uses different channels in both uplink and downlink. This paper mainly focuses on the Downlink channels named as PDCCH, PBCH, PCFICH, PHICH and downlink Signals i.e., PSS and S-SS. The individual Downlink Channels are analyzed using Agilent SystemVue platform further it is synchronized with the Agilent Vector Signal Analyzer (VSA) to the check the Output Response of the individual downlink channels.

Biodiversity research trends and gap analysis from a transboundary landscape, Eastern Himalayas

Pratikshya Kandel,Janita Gurung,Nakul Chettri,Wu Ning,Eklabya Sharma 국립중앙과학관 2016 Journal of Asia-Pacific Biodiversity Vol.9 No.1

The Kangchenjunga landscape, a transboundary complex shared by Bhutan, India, and Nepal, is one of the biologically richest regions in the Eastern Himalayas. Owing to the remarkable biodiversity, the three countries came together to enhance regional cooperation in conservation and development in 2012. To start a strategic conservation intervention, the status of our knowledge base on biodiversity of the landscape is the most important stepping stone. In this paper, we traced the history of biodiversity research in the Kangchenjunga landscape, and present the research trends over time and subject interests. Meanwhile, we also identified key research and knowledge gaps and future priorities. For this, we analyzed 500 peer-reviewed journal articles (until 2014) relating to biodiversity, which were retrieved from the web platform ‘Google Scholar’ and other peer-reviewed journals. The review showed that the landscape received attention from the scientific community as early as the 1840s, and grew progressively after the 1980s. Research on fauna (especially mammals) and flora (especially angiosperms) is most notable, but with major gaps in systematic research of their ecology, whereas invertebrates other than butterflies appear to be neglected. There is a need for systematic research with long-term monitoring that would allow us to understand changes occurring within the landscape.

A theoretical investigation of electronic and optical properties of (6,1) single‑wall carbon nanotube (SWCNT)

D. P. Rai,Y. T. Singh,B. Chettri,M. Houmad,P. K. Patra 한국탄소학회 2021 Carbon Letters Vol.31 No.3

We report the comparative study of electronic and optical properties of (6,1) SWCNT from GGA and DFT-1/2 methods. (6,1) SWCNT is a low-bandgap semiconductor, which falls within ( n1 ? n2)/3≠ integer. The calculated bandgaps are 0.371 eV and 0.462 eV from GGA and DFT-1/2, respectively. Thus, DFT-1/2 enhanced the electronic bandgap by 24.52%. From both GGA and DFT-1/2 approaches (6,1) SWCNT exhibits an indirect bandgap along Γ ? Δ symmetry. However, the percentage change in direct–indirect bandgap is negligibly small, i.e., 4.1% and 3.7% from GGA and DFT-1/2, respectively. The refractive index measured along x-axis ( n x ) approaches unity, indicating transparent behaviour, while that along z-axis ( n z ) goes as high as ∼3.82 for photon energy 0.0 ? 0.15 eV, exhibiting opaque behaviour. Again, the value of n z drops below unity at photon energy ∼0.18 eV and again approaches ∼ 1 for higher energy ranges. The optical absorption is highly anisotropic and active within the infrared region.